184 THE ROYAL SOCIETY OF CANADA 



the anterior end of the ootype in a shght expansion, depending on the 

 number of yolk-cells present, passes forward in the median line above 

 the yolk-ducts but below the ovary, and opens ventral to the opening 

 of the vas deferens in the posterior wall of the genital atrium (Figs. 3 

 and 4) . The vitellaria of the two sides, although extending almost to the 

 forking of the oesophagus, are very distinct in front; but posteriorly 

 in many specimens the boundary between the two appendages which 

 extend into the sucker-bearing region cannot be distinguished. The 

 average condition, however, is that the appendage of the left vitel- 

 larium is quite separate from that on the right side and passes a little 

 farther backwards (Fig. 1). I could not ascertain to my satisfaction 

 whether these appendages surround the posterior ends of the main 

 intestinal trunks. The testes occupy about one-quarter of the length 

 of the body proper, are situated behind the ovary and number about 

 22. The vas deferens commences near the beginning of the ovary, on 

 the right side, then proceeds forward in the median line, dorsal to the 

 uterus, and opens posterodorsally into the genital atrium at the summit 

 of a low elevation which is directed ventrally and slightly forward and 

 is provided at its base with a very few of the spines from the posterior 

 wall of the atrium. Just behind this penis-like structure the vas 

 deferens is surrounded by a fairly extensive sphincter muscle (Fig. 3). 



In the preparation of the foregoing description, which is based 

 on a small number of specimens, it was seen that this worm does 

 not belong to either of the four American species described by 

 Goto (6, pp. 78-83) and that it differs specifically from the eight new 

 species described by MacCallum and MacCallum (Zool. Jahrb., Abth. 

 Syst., 34: 223-244) and MacCallum (Ibid., 35: 389-402), and con- 

 sequently, before MacCallum's recent paper ("Notes on the Genus 

 Microcotyle", in Ibid., 38: 71-78) was at hand, it was named M. poro- 

 noti sp. nov. In order to ascertain whether I was dealing with the 

 same form as that described by Dr. MacCallum I sent my material to 

 him and was kindly assured that without doubt I had found the same 

 species. In correspondence Dr. MacCallum states that this species 

 varies considerably, perhaps on account of age, the testes, for example, 

 ranging from 18 to 32 in fourteen of his mounted specimens, while the 

 organs of attachment on the posterior disc are, as in most of the 

 species of this genus, inconstant in number. 

 4. Otodistomum cestoides (van Ben.) = Stafford's 0. veliporiim 



(Creplin). 11, pp. 521-22; 18, pp. 516-18; 26, pp. 482-83. 



Stomach of Raja laevis. 



Specimens at hand range in length from 12 to 48mm. The 

 eggs average in length, 0-070, in width, 0-042 and in thickness of 

 shell, 0- 0028mm. 



